Hydraulic transmission and clutch



.June 2l, 1949. R. l. CUMMING 2,473,638

HYDRAULIC TRANSMISSION AND CLUTCH INVENToR.

Jue 2l, 1949. l R. lfcuMMlNG 2,473,638

HYDRAULIC TRANSMISSION AND CLUTCH Filed sept. 14, 1944 2 shetsfsheet 2 A N VEN TOR. Fe'fd/J @wp/Z515.

Patented June 21, 1.949

iJiTED S OFFICE HYDRAULC TRANSMISSION AND CLUTCH Application September i4, 1944:, Serial No. 554,008

(Cl. i4- 688) 6 Claims.

This invention relates to variable speed transmissions and more particularly to a hydraulic clutch and forward speed transmission mechanism by means of which varying speed ratios may be obtained between a, driving element or input shaft and a driven element or output shaft.

An object of the invention is to provide an improved hydraulic transmission unit which is relativelysimple and compact in construction, eflicient and durable in operation and which is adaptable for a variety of uses where it is desired to transmit at varying speeds to a driven shaft or element the torque of a driving element or input shaft.

A further object of the invention is to provide an improved hydraulic clutch or transmission unit by which varying speed ratios are obtained through the medium of relatively rotatable impeller and housing elements coaxially arranged and provided respectively with radially extending blades or ns cooperable during relative rotation of the elements to transmit rotative effort from one to the other in improved and efficient manner.

Another object of the invention is to provide a hydraulic transmission and clutch in which the torque of the input shaft is transmitted by a hydraulic impeller unit through a set of planetary gearing to the output shaft and in which the speed ratio of the latter is varied through the medium of a second hydraulic impeller unit U adapted to control the speed characteristics of the sun gear of the planetary gear set.

Still a further object of the invention is to provide an improved hydraulic transmission having relatively rotatable housing and impeller elements, one secured to the input or driving shaft and the other carrying the internal gear of a planetary gear set, the planet pinions of the set being carried by the output shaft and normally adapted to transmit a predetermined maximum speed thereto less than that of the input shaft, and in which the speed of the output shaft may be varied by` controlling the sun gear of the planetary gear set through the medium of a second impeller element associated and cooperating with a housing which is common to both impeller elements of the transmission.

Another object of the invention is to provide a hydraulic or uid clutch embodying relatively rotatable housing and impeller elements drivinglyl connected one to an input shaft and the other to an output shaft or the like and in which the transmission of power from one element to the other is accomplished by means of radially extending blades or fins on the impeller movable within an annular space formed by radially extending blades or fins extending inwardly from the inner walls of the housing, the improved construction being such that during relative rotation of the housing and impeller elements the planes of successive blades or iins of one element have instantaneous coincidence with the planes of successive blades or fins of the other element.

A further object of the invention is to provide a hydraulic clutch or transmission unit having a rotatable impeller mounted within a rotatable housing and coaxial therewith, the impeller having radially extending blades or vanes movable between similarly arranged internal vanes or rlns on the housing, the transmission of power being accomplished by differential pressures created between adjacent faces of the respective blades as each blade of the impeller passes through and beyond a position in which it is instantaneously coplanar with an adjacent blade or n of the housing, the improved operation also being such that a circulation of the hydraulic medium in a radial direction is induced between each adjacent pair of blades or fins thus permitting effective dissipation of heat and eiiicient control of the temperature of the hydraulic medium.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying draw-- ings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. 1 is a central longitudinal sectional view of a hydraulic clutch or transmission constructed in accordance with the invention.

Fig. 2 is a section taken substantially through lines 2 2 of Fig. 1 looking in the direction of the arrows.

Fig. 3 is a section taken lines 3 3 of Fig. l looking arrows.

Fig, 4 is a central longitudinal sectional view illustrating another embodiment of the invention.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invenn tion is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to Figs. 1 to 3 inclusive, wherein one embodiment of the invention is villustrated by substantially through in the direction of the way of example, the input or drive shaft is shown at I0 having a driving fiange I I by which it may be drivingly connected to a prime mover or other driving element, such as a crank shaft or propeller shaft. In the present transmission unit the driving mpeller;` generally designated at I2, is prvided with e heb 12a spiined or keyed te the shaft I0. Arranged in line with the shaft I0 is an intermediate shaft I3, herein termed the variable speed shaft, and keyed or splined to this shaft is the hub ma ef a variame speed iipeile'r I4. The shaft I3 has a projecting pilot portion I3a extending into an annular recess iii the inner end of an output or driven shaft I5 arranged coL axially with the shafts I0 and I3.

The driving and variable speed impellers are mounted within a unitary housing formed of v`a plurality of annular sections. The cylindrical housing for the impeller I2 comprises two sections I6 and I'I provided with radially extending external 'cooling fins I8 and I9. These sections have n'nularly extending flanges' I'S, and l'l arranged face to face in abutting relatiqn and bolted together at 20 to provide a liqiiid tight joint. It Will be understood that 7a. gasket is interpos'd in pratic b'etWe'en these attaching an'g's in order to ensure 'against leakage of the oil or other hydraulic ""edifurl 'vvithiii the housmg'. IProjecting from the Housing section .111 is an ihtglal hoil'i'g th 2l f "Sihller `til-ain'- eter having an annular v'atta'c'zhin'g `flange 2Ia ai'- rariged face to face with a correspnding attaching fiange 22a on 'a housing 'section 22. "Ihese flanges a'r bolted together at 23 with a gasket interposed therebetween vto provide -a seal. As in the 'case o'f the housing sections I6 and II,`th`e housing 'sections 2I 'and `22 provide fan annular cylindrical chamber within wnieh is netted the variable speed lmpellei I4. v

Projecting inwardly from the side Walls resp'e'ctively of the housing sections I6 Aand I l are radially extending fi'ns, blades `or baffles 24 and 25. Each blad'e 24 and 2 5 at its buter end has an intgral right afng'ularly extending extension 24a and 25h respectively which projectsforn the outer Wall of the housing s'ectionraiially inwardly. `Each pair "of yfins 24 "and '25 lifes in a single plane and the-'fin extensions 2*'4a and 25a of 'each pa'i'r moet at their 'ends andare coplana-r. Thus, in erfee't, there i'eepreviued ing I6', II for the driving irripellei a series of radially extending circuinfe'r'entially spaced U'- shaped iin members Yeach comprising coplanar portions 2'4', 24u, 25u Aand 25 extending Asubst-antially continuously around 'threesides of the -interio'r of the housing a "dformlng tacentrai opening or passage through Awhich the `i`rnpell er i s adapted to rotate. Each adjacent pair -'of 'nn members, Vthus formed, 'defines 7a :channel of 'uniform depth which 'is vgenerally V-shaped having radial side Walls which diverge outwardly and terminate iat the outer annular 'ivall of th'e houslng.

The impeller I2 comprises a vdisk or Web 26 having a series of ns or'blades 21 extending 'from opposite sides thereof. These blades or vanes project radially from the hub I`2a and, hence, diverge outwardly. The "blades 21 of eachpair are coplanar Vand occupy an area slightly less than the area of the opening or space betwen'the 2li-25, thus permttng'the marglnal'dges of 'the impeller blades to just clear the marginal edges of the housing fins "during relative rotation 'of the l'iousin'garid iipeller.

The housing for the lVariable speed impeller,

within the 4housformed by sections 2l and 22, is constructed with a finned` passage for the impeller similarly to the housing for the driving impeller. Projecting inwardly from the inner side walls respectively of the variable speed impeller housing are radially extending ns, blades or baies 28 and 29, each of which at its outer end having an integral right angularly extending extension 28a and 29a respectively projecting from the outer wall of the housing. The flns 28 and 29 with their extensions -28a and 29a are arranged in coplanar pairs in the same manner as the fins 24 and 25 with their outer angular extensions 24a and 25a.

The impell'er Iii comprises a disk or web 30 having a series of fins or blades 3| extending from opposite sides thereof and projecting radially 'from the hub yIdd of the irnpeller. These blades are arranged in pairs with the blades of each pair coplana'r, similarly to the blade construction of the impeller I2. Thus, the variable speed irnpell'ei' Iii with its 'outwardly diverging radial blades 3| is rotatable Within an annular passage formed between 'the M528, 29 of the housing and occupies an area slightly less than the 'area of the space between the finned portions of the hous ing so as to just clear the edges thereof during relative rotation o'f the housing and impeller.

The housingsection I6 has a main bearing 32 on the shaft I I! and bearings 33, u311 at 'adjacent reduced ends of the shafts II) and I3. 'I he housing section 22 is preferably provided with cooling fins Isa and is supported by a bearing 35 on the intermediate shaft I3. Bolt'ed 'at 3B to the `housing section 22 is an end housing section 31 which has a bearing at 3B on the output shaft I5. Integral with the inner end of the shaft 'I5 is an annular flange 3'9 Within which fare fastened a series 'of four stud shafts llt carrying 'planet gears or 'pinions tI. llhese yp lnions mesh with a ring or internal gear 42 rigidly secured by bolts I3 to the housing section 22. The planet 'pinions 'also mesh with a 'reaction sun gear 44 keyed to the intermediate shaft I 3.

vIt will be s eenthatthe 'n iain housing 'composed of 'sections it, 1 1, 2'2 and e1 is adaptedto rotate es a. unit 'relatively re the input shaft and is divided linto v'three compartments within 'which are housed the driving iinpeller, the variable speed impeller and the planetary gear lset 'comprising ring gear-82, planet gears 4I and sun 'gear 44. The housings for the imp'ellers are conveniently provided with filler `openings through which the hydraulic medium, such as loil, may be introduced 'therein to lfill the housing, these openings being closed by plugsffi and "46. The entire housing is `made liduid-tight-fso as to contain the hydraulic medium therein against 'appreciable leakage 'during `continued use. 'Accordingly, packing :glands '41 Vande-8 are provided 'at opposite ends uof the housing for this purpose.

Tn ioperationtheshaft IIl is rotated to transmit rotative `motion to the Viinpe'll'er I`2 through its splin'ed :connection thereto. As the impeller rotates within'the annular spaceorpass'age 'formed f between the 'marginal 'edges 'ef-the housing "nhs 2t, '25, pressure 'or the Hydraulic medium is built u p in advance of the leading facesof theblades 2'I and va 'reduced lor negative pressure at Athe rear faces thereof, thus exerting a drag or pull on the housing 'fins -and `n'ipar-tin'g rotative motion te the heueingjm 'the direction ef rotation 'ef the-'i'ipelle'lt This 'motion is 'transmitted taintnal gear vi12, 'which is lflfsie'r'lefl t'o the housing, eine 'sineje this 'gear is 'in mesh with thepianet planet pinions will be rotated both about their own axes and also bodily around the sun gear fifi with which they are in mesh. This motion of the planet gears around the sun gear will be transmitted to the driven shaft. Assuming that the shaft i3 is stationary and the sun gear is not turning on its own axis, the driven shaft I5 will rotate at one half of the speed of the input shaft it when the housing has attained the same speed or rotation as the impeller I2. The interval of time required for the housing speed to attain that oi the driving impeller will depend upon the torque effort and the load imposed upon the output or driven shaft I5. Since this load is divided equally between internal gear 42 and sun gear tbl, which assumes the torque reaction, it will be seen that the variable speed impeller unit need be but one half the size of the driving impeller unit and correspondingly smaller in capacity. Thus, the blade of iinned area of the impeller Ill and its housing is one half that of the impeller I2 and its housing. l

The speed ratio of two to one between the shafts tti and I 5, which would be obtainable if the sun gear lid remained stationary, is varied up to a one to one ratio through the medium ofthe variable speed propeller unit. Since the entire housing rotates as a unit by reason of the operation of the main impeller I2, the housing sections 2t and 2E will also initially rotate around the impeller it.. This action will create a pressure of the fluid in advance of the housing fins 28, 29 and a reduced pressure behind these ns, thereby producing a drag or pull upon the impeller blades 3| and a consequent rotation of the impeller I4. Rotativo motion of this impeller is transmitted through shaft I3 to the sun gear 44. As the speed of rotation of the sun gear increases, the speed of rotation of the planet pinions about their own axes decreases proportionately, thus producing a proportionate increase in the speed of rotation oi the driven shaft. When the impeller I4 and the sun gear are rotated at the same speed as the housing, assuming that the housing has attained the same speed as the driving impeller, then a one to one ratio is attained resulting in a direct drive from the shaft I0 to the shaft I5. Under these conditions the entire transmission unit will be immobilized, that is, the entire housing, the impellers and the gear train will turn as a unit without any relative motion between any of the gears or between the impellers and the housing. From the foregoing it will be seen that by virtue of the present hydraulic transmission and clutch unit virtually any speed ratio may be obtained between the input and output shafts up to a direct drive ratio of one to one. The operation of the impellers in association with the nned housing is highly efficient not only in the transmission of power but also in respect to minimization of heat losses and consequent loss of power. Excessive heating of the fluid medium is also prevented by an induced circulation of 'the oil within the channels between the fins of the housing and the blades of the impellers. Relative rotation of the impeller and housing creates a low pressure zone at the outer end of the housing at the trailing sides of the impeller blades, thus inducing an outward ilow of oil within the channels between the impeller blades. The oil moving in the channels toward the outer end of the housing is forced by the blades outwardly and thence laterally causing it to flow radially inwardly through the channels between the housing ns. A continuous circulatory flow of oil, as shown by the arrows in Fig. 1, is set up by the relative rotation of the housing and impellers-thereby malntaining a relatively low temperature of the oil and enabling heat to be more effectively dissipated through the walls of the housing and the cooling ns I3, I 9 and I 9a. In addition to the foregoing features of the present transmission, a further fea-ture by which improvement in operation is obtained resides in the ared construction of the channels between the blades or fins of the housing and impeller members. Furthermore, greater effectiveness in the transmission of torque is achieved by providing a considerably less number of blades on the impeller than ins on the housing so that the distance between the outer ends or adjacent impeller blades will be considerabiy greater than between adjacent 1in portions.

The embodiment illustrated in Fig. 4 is similar in many respects to the previous embodiment, differing therefrom principally in that the transmission or hydraulic clutch unit consists of a single impeller assembly for transmitting power directly from a drive element to a driven elementV without the interposition of a reaction impeller unit and a planetary gear set. A single fluid tight annular housing comprising two. sections '3S and 5I) having attaching flanges bolted together at 5I is provided in this embodiment. The housing sections are formed with radial internal fins 52 and 53 constructed and arranged in identically the same manner as the hns 2d, 24a, 25 and 25a of the previous embodiment. The housing 49, 59 is journalled through suitable bushings on an impeller hub 54 which in turn is splined to the input shaft 55. The impeller hub is formed with an iinpeller 56 comprising a disk or web provided with radial vanes or blades 5l. This impeller is constructed identically to the impeller I2 and functions in cooperation with the vanes or fins 52, 53 in the same manner as the driving impeller unit of the previous embodiment. Preferably formed integrally on the outer side of the housing section 5B is a pulley or sheave 58 grooved to receive a pulley belt 59'by which power may be transmitted to any desired driven member through a companion sheave or pulley on the latter. The operation of the device shown in Fig. 4 by which power is transmitted hydraulically frorn shaft 55 and impeller 56 to the houslng 4Q, 5t through its ns or vanes 52, 53 and thence to the belt 5s will be readily understood from the description of the operation of the previous embodiment.

I claim:

1. In a hydraulic transmission, a rotatable housing unit comprising two adjacent annular chambers adapted to contain a hydraulic medium and each provided with a series of diverging radially extending fins, each iin comprising portions within the chamber extending inwardly in the same plane from the side and end walls of the chamber, a pair of impellers coaxial with the housing unit and disposed within said chambers, each impeller having a series of diverging radially extending fins movable within the annular space formed between the inner edges of the ns of the associated chamber, means for supporting said impellers for rotation one independently of the other, a driving element connected to one impeller, a driven element, and gearing connecting the driven element, housing unit and second impeller.

2. In a hydraulic transmission, a rotatable housing unit comprising two adjacent annular chambers adapted to contain a hydraulic medium and each provided with a series of diverging radially extending iins, each iin comprising portions within the chamber extending inwardly in the same plane from the side and end walls of the chamber, a pair of impellers coaxial with the housing unit and-disposed within said chambers, each impeller having a series of diverging radially extending fins 4movable within the annular space formed between the inner edges of the ns of the associated chamber, means for supporting said impellers for rotation one independently of the other, means for driving one impeller, a driven element, and a planetary gear set for varying the speed of the driven element including an internal gear on the housing unit, planet gears carried bythe driven element and a sun gear drivingly connected -to the second impeller.

3. In a hydraulic transmission, a vrotatable housing unit comprising two adjacent annular chambers, an impeller within each chamber, said impellers and housing unit being arranged coaxially, radially extending fins extending inwardly from the inner walls of .the chambers and cooperable with radially extending tins on the impellers, means for driving one impeller, a driven element, planet gears carried lby the driven element, an internal gear on the housing meshing with said planet gears, and a sun gear meshing with the planet gears and connected Yto the second impeller.

4. In a hydraulic transmission, a rotatable housing unit comprising two adjacent annular chambers, an impeller within each chamber. said impellers and housing unit being arranged co-axially, radially extending fins extending nwardl'y from the inner walls of the chambers and cooperable with radially extending ns on the impellers, means for driving one impeller, a driven element, planet gears carried by the driven element, an internal gear on the housing meshing with said planet gears. and a `sun gear meshing with the planet gears and connected to the second impeller, said second ime peller and associated chamber having less iin area than the iirst named impeller and its as sociated chamber.

5. In a hydraulic transmission, a rotatable housing unit comprising two adjacent annular chambers, an impeller within each chamber, said impellers and housing unit being arranged co-axially, radially extending fins extending inwardly from the inner walls of the chambers 8. and cooperable with radially extending iins on the impellers, means for driving one impeller. a driven element, and a variable speed gear set connecting the driven element, housing unit and second impeller, said gear set including a mem bet rotatable with said second impeller.

6. In a hydraulic transmission, a rotatable housing unit comprising two adjacent annular chambers adapted to contain a hydraulic medium and each provided with a series of diverging radially extending iins. each fin comprising portions within the chamber extending inwardly in the same plane from the side and end walls of the chamber, va pair of impellers coaxial with the housing unit and disposed with in .seid chambers, each impeller having a series of diverging radially extending fins movable Within the annular space formed between the inner edges of the iins of the associated chamber, 'means for supporting said impellers for rotation one independently of the other, a driving element connected to one impeller, a driven element. and variable speed gearing interposed between the driven element, housing unit and second impeller, said gearing including a sun gear rotatable with said second impeller.

REGINALD I. CUMMING.

REFERENCES CITED The `following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,203,265 Radcliie Oct. 31, 1916 1,212,974 Pinckney Oct. 16, 1917 1,540,453 Arave June 2, 1925 41,636,050 Fottinger July 19, 1927 1,918,163 Wohlenhaus July 11, 1933 1,927,616 Rudquist Sept. 19, 1933 2,129,884 Swan Sept. 13, 1938 2,131,619 Dueld Sept. 27, 1938 2,212,774 Guyer Aug. 27, 1940 2,292,482 Roche Aug. 11, 1942 2,315,130 Peterson Mar. 30, 1943 2,368,873 Pollard Feb. 6, 1945 2,388,062 Keller Oct. 30, 1945 FOREIGN PATENTS Number Country Date 372,983 Great Britain May 19, 1932 407,146 Great Britain Mar. 15, 1934 546,009 France Oct. 26, 1922 

